I did a 200 mile run with my trailer and pulled into a rest stop checked the wheels just touching the hub.
One side was cool the other it was ten minutes before I could touch it.
I quickly ruled out the bearings as I had an issue with the brakes
grabbing when I hooked up.
Once home I decided to check and pulled the wheels, driver side brake had been dragging not releasing properly and given that cob webs were in the housing of the other side it was not working.
In the end I replaced the complete brake assemblies with never adjust Dexter and replaced the hubs as the seals were gone anyway.
I could have just put new seals and other parts in but looking at the complete assemblies that were on I figure a small investment to bring everything back to new was better.
The bearings looked good no signs of heat.
The point is heat could also be brakes